The present invention relates to brushless exciters for generators.
Conventional power generators include an exciter which is normally mounted at one end of the generator rotor shaft. Known exciters include a rotor mounted on the shaft of the generator rotor and provided with armature windings, rectifier components and output conductors via which a direct current is supplied to the generator rotor windings. The exciter rotor is enclosed by a stator provided with components which produce a stationary magnetic field.
In exciters of this type, the armature windings include end turns which must be securely supported, typically by fiber glass bands, in order to resist the centrifugal forces imposed thereon during generator operation. Manufacture of the rotor is made difficult by the fact that only a limited space is available for the armature windings. This limited space and the presence of supporting bands on the armature winding end turns additionally increase cooling problems.
Furthermore, because of various inherent structural limitations, including the desire to minimize the centrifugal forces imposed on the rotor armature winding end turns, the diameter of the exciter air gap must be maintained at a relatively small value.